UNIVERSITY  OF   CALIFORNIA 

COLLEGE    OF    AGRICULTURE 

AGRICULTURAL    EXPERIMENT    STATION 

BERKELEY,    CALIFORNIA 

CIRCULAR  304 

March,  1926 

DRAINAGE  ON  THE  FARM 

WALTER  W.  WEIR 


A  well  built,  substantial,  concrete  outlet  protection  for  a  tile  drain. 


•    FOREWORD 

This  circular  is  intended  to  cover  the  principles  and  methods  of 
drainage  of  wet  lands  in  California  and  is  applicable  to  those  parts 
of  the  state  which  do  not  require  the  special  considerations  essential 
in  the  drainage  of  lands  where  alkali  is  a  factor. 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


NEED    FOR    DRAINAGE 

Almost  every  farm  contains  some  land  that  could  be  improved  and 
made  to  produce  more  or  better  crops  by  some  type  of  drainage.  This, 
rather  than  the  presence  of  swamps,  ponds  or  springs,  usually  deter- 
mines the  need  for  drainage. 

Good  slopes  or  even  hillsides  do  not  necessarily  insure  adequate 
natural  drainage,  although  such  slopes  will  greatly  facilitate  the 
correction  of  poor  drainage  conditions.  The  greatest  need  of  drainage, 
however,  occurs  in  flat,  level  areas  or  basins  which  are  made  up  largely 
of  heavy-textured  soils  or  soils  having  relatively  impervious  subsoils. 


Fig.  1. — A  typical  poorly  drained  grain  field  showing  patches  where  the 
grain  has  been  drowned  out  or  stunted. 


BENEFITS    OF    DRAINAGE 

There  are  many  benefits  to  be  derived  from  drainage.  The  most 
obvious  is  the  removal  of  ponds  and  the  drainage  of  swamps  to  permit 
the  growth  of  crops  where  it  would  otherwise  be  impossible.  Land 
of  this  type,  however,  constitutes  only  a  small  proportion  of  the  area 
which  could  be  improved.  Most  of  the  land  that  would  be  benefited 
by  drainage  can  be  farmed  and  some  crop  obtained  without  drainage. 
Figure  1  shows  a  poorly  drained  grain  field  in  which  part  of  the 
grain  has  been  drowned  out.  Drainage  would  improve  the  granu- 
lation or  tilth  and  improve  the  aeration  of  such  land  and  raise  its 
temperature  during  the  early  season,  and  thus  promote  early  develop- 


Circ.  304] 


DRAINAGE    ON    THE    FARM 


ment  of  the  crops.  It  would  also  very  materially  lessen  the  effects  of 
drought  during  the  dry  season  and  by  quickly  removing  the  excess  of 
water  from  wet  places  permit  entire  fields  to  be  planted  or  cultivated 
at  one  time.  Other  benefits  follow,  such  as  the  more  rapid  development 
of  useful  microorganisms,  which  accelerate  chemical  reactions  and 
increase  the  availability  of  plant  food  elements  there  is  less  danger 
from  frost  injury;  and  the  plants  are  rendered  less  susceptible  to 
disease  or  parasitic  injury. 

Drainage  does  not  remove  any  water  which  is  in  a  form  available 
for  use  by  the  plants.  It  removes  only  the  free  water  existing  in  the 
soil  in  excess  of  that  necessary  to  wet  it  to  capillary  capacity.  The 
removal  of  this  excess  water  increases  the  mass  of  soil  wetted  with 
only  capillary  or  available  water.  There  are  few  useful  plants  which 
will  thrive  with  their  roots  in  saturated  soil. 

ENGINEERING    ASSISTANCE 

Too  much  stress  can  not  be  laid  on  the  advisability  of  securing 
reliable  engineering  advice  before  installing  a  drainage  system.  The 
owner  rarely  has  the  training  or  experience  which  will  enable  him 
to  design  and  construct  the  best  and  most  economical  system.  The 
designing  of  large  comprehensive  drainage  systems,  involving  the 
organization  of  drainage  districts  or  cooperation  among  a  number  of 
owners,  is  usually  conceded  to  require  the  services  of  an  engineer,  but 
no  less  ability  is  often  required  to  properly  design  and  lay  out  a 
system  involving  only  a  few  hundred  feet  of  drain.  Good  engineering 
advice  is  cheaper  than  poor  drains.  The  careful  engineer  makes  a 
survey  not  only  of  surface  conditions  to  determine  the  direction  in 
which  drains  should  run  and  the  fall  available,  but  also  carefully 
examines  the  subsoil  with  a  soil  auger  to  assist  in  determining  the 
best  location  of  a  drain,  its  depth,  and  the  proper  spacing  between 
drains.  To  determine  the  proper  size  of  a  drain  for  the  slope  and 
the  amount  of  water  to  be  removed  also  requires  study  and  com- 
putation. 

THE    OUTLET 

No  system  of  drainage  will  prove  entirely  satisfactory  or  give  the 
maximum  results  without  a  good  and  adequate  outlet.  The  first  step 
in  planning  for  drainage  is  to  ascertain  the  suitability  of  the  outlet. 
If  a  channel  which  will  provide  free  flow  for  the  discharge  of  the 
proposed  system  can  not  be  found  one  must  be  provided.  This  may 
require  very  careful  planning  to  use  most  advantageously  all  available 
fall.    To  secure  an  outlet  it  will  often  be  necessary  to  cooperate  with 


4  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

a  neighbor  or  obtain  permission  to  cross  other  property.  The  ideal 
outlet  provides  a  free  flow  from  the  main  drain  at  all  times  and 
allows  the  construction  of  the  main  drain  at  a  good  depth.  (See  cover 
picture. )  This  does  not  imply,  however,  that  unless  an  outlet  meeting 
all  of  the  ideal  requirements  can  be  secured,  the  proposed  drainage 
project  must  be  abandoned.  Under  certain  conditions  the  main  drains 
may  be  submerged  for  short  periods  during  storms  without  serious 
damage.  In  the  drainage  of  tidal  marshes  the  outlet  is  frequently 
through  tide  gates  which  are  closed  for  several  hours  each  day,  yet 
satisfactory  drainage  is  provided. 


Fig.  2. — Open  drains  waste  valuable  land,  harbor  weeds  and  injurious 
insects  and  require  considerable  maintenance. 


TYPE    OF    DRAIN 

There  are  two  general  types  of  drains,  each  of  which  may  be 
modified  in  many  ways  to  suit  local  conditions.  These  are  the  open 
drain,  or  drainage  ditch,  and  the  covered  drain,  or  buried  conduit. 
Covered  drains  are  usually  of  tile.  The  type  of  drain  selected  for 
any  particular  place  depends  upon  the  requirement  to  be  met  and  the 
wishes  of  the  owner. 

Open  Drains. — Open  drains  have  an  advantage  over  tile  where 
large  quantities  of  surface  water  are  to  be  removed  rapidly,  as  for 
instance,  providing  an  outlet  for  run-off  from  a  hillside  during  a 
heavy  rain,  or  as  an  outlet  for  a  large  tile  drain.    Where  large  areas 


Giro.  304]  drainage  on  the  farm  5 

are  drained  and  the  land  is  not  of  great  value,  the  ditch  is  most 
frequently  used  because  it  carries  a  large  amount  of  water  more 
economically  than  tile.  On  the  other  hand,  open  drains  constructed 
across  a  field  are  at  best  unsatisfactory  and,  if  deep  enough  to  ade- 
quately drain  the  subsoil,  they  require  a  considerable  area  of  land, 
which  might  otherwise  be  farmed.  Often  a  combination  of  tile  and 
open  ditch  is  used.  In  this  case  a  broad  shallow  ditch  carries  off 
flood  waters  while  beneath  it  a  tile  line  completes  the  work  by 
draining  the  subsoil. 

Open  drains  may  be  a  source  of  danger  to  stock  unless  properly 
fenced;  harbor  obnoxious  weeds,  plant  diseases  and  rodents;  and 
require  consistent  maintenance  to  be  always  fully  efficient.  Figure  2 
illustrates  a  badly  obstructed  open  drain. 


1 


Natural   System  Intercepting   System  Gridiron   System  Herring   Bone   System 

Fig.  3. — Various  arrangements  of  drains.  Frequently  drainage  systems  as 
actually  constructed  involve  a  combination  of  two  or  more  of  these  arrangements. 

Tile  Drains. — Tile  drainage  offers  the  most  efficient  and  permanent 
method  of  draining  land.  The  tile  are  placed  underground  where 
they  do  not  interfere  with  cultivation  and  when  properly  laid  require 
very  little  attention  to  keep  them  in  operation.  Although  it  is  neither 
good  engineering  nor  good  farming  to  be  ignorant  of  the  exact 
location  of  underdrains,  many  farms  are  being  successfully  drained 
year  after  year  by  tile,  the  location  or  even  the  presence  of  which 
may  not  be  known  to  those  who  operate  the  farms. 

Tile  drains  lend  themselves  to  more  variation  in  design  than  do 
open  drains  because  of  the  fact  that  they  do  not  interfere  with  culti- 
vation. In  general  there  are  four  arrangements  (see  Figure  3)  which 
can  be  used  either  in  the  true  form  or  in  combination.  There  is  no 
best  arrangement  for  all  conditions.  Each  field  must  be  surveyed  and 
studied  to  determine  its  own  particular  needs. 


6  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

SURVEY   AND    PLANS 

When  the  outlet  has  been  decided  upon,  a  complete  survey  should 
be  made  of  each  area  that  requires  drainage.  This  survey  should 
include  all  areas  which  will  have  a  common  outlet  whether  it  is 
intended  to  drain  them  at  this  time  or  not.  If  only  a  portion  of  the 
work  is  to  be  done  at  one  time,  it  should  be  planned  with  the  future 
extensions  in  view.  If  this  is  not  done,  some  portion  of  the  work, 
usually  the  main  drain,  may  be  found  inadequate  to  care  for  additional 
areas  when  they  are  added.  As  a  drain  is  constructed,  its  location  should 
be  noted  exactly  on  the  plan.  It  is  not  sufficient  to  rely  on  the  original 
plan,  which  is  made  before  construction  begins,  for  frequently  minor 
and  sometimes  major  changes  are  made  during  construction.  All 
survey  notes  and  plans  should  be  carefully  preserved,  as  the  time  may 
come  when  they  will  be  badly  needed. 

DESIGN    OF    OPEN    DRAINS 

For  areas  up  to  160  acres,  drains  should  be  designed  to  remove 
about  one  surface  inch  from  the  tract  in  twenty-four  hours.  If  water 
reaches  the  tract  from  other  sources,  the  entire  contributing  area 
should  be  considered  rather  than  merely  the  area  it  is  proposed  to 
drain.  For  larger  tracts  the  main  drain  may  be  designed  for  a 
run-off  of  only  three-fourths  inch  in  twenty-four  hours.  Conditions 
of  tilth,  topography,  and  soil  are  determining  factors  in  the  rapidity 
and  amount  of  run-off.  In  a  gently  sloping  field  in  good  tilth,  the 
soil  will  retain  much  more  water  than  in  barren  or  untilled  fields 
or  in  those  having  greater  slopes.  The  size  of  ditch  required  to  carry 
a  given  amount  of  water  is  dependent  upon  the  slope  or  grade  and, 
to  a  less  extent,  upon  the  shape  of  its  cross-section ;  the  shape  is  deter- 
mined by  the  kind  of  soil  through  which  the  ditch  passes. 

In  ascertaining  the  size  of  an  open  drain  required  to  carry  a  given 
quantity  of  water  on  a  given  grade,  Elliott's  formula  for  open  drains 
has  been  found  satisfactory  and  because  of  its  simplicity  is  more 
convenient  to  use  than  some  others,  which  may  under  certain  con- 
ditions be  slightly  more  accurate. 


-v 


ax  iy2  f 

P 
where  v=velocity  in  feet  per  second 

a=area  or  cross-section  of  drain  in  feet 
p— wetted  perimeter  in  feet 
f  =fall  in  feet  per  mile 
Q=quantity  in  cubic  feet  per  second 


CIRC.  304]  DRAINAGE   ON   THE   FARM  7 

When  the  velocity  is  found  the  quantity  of  water  carried  "Q"  is 
obtained  from  the  following  formula : 

Q=av 

An  open  drain  should  be  deep  enough  and  wide  enough  to  carry 
the  maximum  flow  without  overtopping  its  banks,  and  to  carry  the 
normal  flow  well  below  the  general  ground  surface.  The  banks  of  the 
ditch  should  be  .sloped  to  such  an  extent  as  to  prevent,  as  far  as 
possible,  any  caving  when  they  are  wet.  In  clay  the  side  slopes  may 
be  as  steep  as  one-half  foot  horizontal  to  one  foot  vertical,  while  in 
sandy  soils  it  may  be  necessary  to  make  the  slopes  as  flat  as  two  or 
more  feet  horizontal  to  one  foot  vertical.  The  excavated  material 
should  be  placed  some  distance  from  the  edge  in  order  to  prevent  it 
from  slipping  back  into  the  drain.  A  safe  rule  to  follow  for  ditches 
under  twenty  feet  in  top  width  is  to  place  excavated  material  so  that 
the  berm,  or  strip  of  land  between  the  edge  of  the  ditch  and  the  toe 
of  the  waste  bank,  is  equal  to  one-half  the  top  width  of  the  ditch. 

Team  and  scraper  ditches  are  sometimes  used  where  surface  water 
accumulates  in  considerable  quantities  and  the  drain  is  required 
simply  to  remove  it  quickly.  Drains  of  this  nature  are  expected 
to  be  dry  most  of  the  time  and  are  so  dug  as  to  be  of  least  hindrance 
to  cultivation  and  cropping.  In  many  cases  cultivation  is  continued 
over  such  drains. 

Open  drains  dug  by  hand  are  necessarily  limited  to  rather  small 
ditches,  seldom  over  three  or  four  feet  wide  on  top  and  four  or  five 
feet  deep.  Ditches  of  this  type  cause  the  least  inconvenience  when 
located  along  fence  or  property  lines.  Figure  4  illustrates  the  relation 
between  depth,  side  slopes  and  width  of  berm  for  a  hand  dug  ditch 
in  heavy  soil. 

The  banks  of  open  drains,  at  the  points  where  surface  water  enters, 
must  be  protected  so  as  to  prevent  erosion,  which  not  only  destroys 
the  banks  and  wastes  land  but  also  fills  up  the  drain  and  impairs  its 
efficiency.  Surface  water  may  be  admitted  to  an  open  drain  through 
a  box  or  culvert  under  the  waste  bank.  When  properly  constructed, 
such  a  box  will  be  a  protection  against  washing  of  the  ditch  bank. 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    .STATION 


CONSTRUCTION     OF     OPEN      DRAINS 

Open  drains  are  constructed  in  three  ways:  by  machinery,  with 
teams  and  scrapers,  and  by  hand.  There  are  several  types  of  exca- 
vating machinery  for  digging  open  drains ;  these  vary  in  size  from  the 
large  floating  or  dragline  dredge  capable  of  excavating  drains  up  to 
100  or  more  feet  in  width,  to  the  excavator  which  will  dig  a  drain 
three  or  four  feet  in  width.  For  farm  drains,  however,  only  the 
smaller  types  of  excavators  are  used,  and  these  only  on  the  larger 
farms,  or  where  several  farmers  unite  in  a  general  plan  of  drainage. 
When  drains  are  constructed  during  the  dry  season,  teams  may  be 
used.  Ditches  excavated  in  this  way  are  necessarily  limited  to  rather 
shallow,  broad  drains  in  soils  stable  enough  to  permit  the  driving  of 
teams  over  them.  Digging  drains  by  hand  is  feasible  only  when  they 
are  small  enough  to  allow  the  excavated  material  to  be  disposed  of 
without  rehandling. 


mm 
^P^fe*  3 


3 '  Berm 


lilt  ; 

Fig  4. — A  type  of  hand  dug  ditch  suitable  for  heavy  soils. 
MAINTENANCE    OF    OPEN    DRAINS 

Open  ditches  require  a  considerable  expenditure  for  maintenance. 
It  is  this  item  that  makes  the  final  cost  of  open  drains  equal  to  or 
above  that  of  underdrains.  In  order  to  maintain  the  efficiency  of 
a  ditch,  it  is  necessary  to  clean  it  at  least  once  each  year.  Brush  and 
weeds  that  are  certain  to  grow  during  the  dry  season  must  be  removed, 
caving  banks  must  be  repaired,  and  all  obstructions  such  as  temporary 
fences,  rubbish,  etc.,  removed  before  the  we1  season  begins.  After 
a  year  or  two  it  may  be  necessary  to  reexcavate  in  order  to  maintain 
the  desired  depth.  If  these  things  are  not  done,  conditions  may  soon 
become  as  bad  as  they  were  before  the  ditch  was  constructed.  The 
cost  of  maintenance,  of  course,  varies  with  the  amount  of  excavation 
and  repair  work  necessary;  in  a  few  years  it  may  amount  to  a  con- 
siderable proportion  of  the  first  cost. 


ClRC.  304]  DRAINAGE   ON    THE   FARM 


DESIGN    OF    TILE    DRAINS 

Location.— The  location  of  the  main  drain  will  be  controlled  largely 
by  the  position  of  the  outlet,  the  size,  shape  and  slopes  of  the  area 
to  be  drained  and  the  location  and  depth  of  the  laterals.  On  the  other 
hand,  the  location  and  depth  of  the  main  drain  will  have  much  to  do 
with  the  location,  cost  and  efficiency  of  the  lateral  drains.  Usually 
the  main  drain  follows  the  lowest  of  the  natural  depressions  with 
submains  following  the  minor  depressions.  In  the  natural  system  as 
illustrated  in  figure  5,  this  is  all  the  drainage  that  is  required. 

In  the  foothill  areas,  the  intercepting  system  is  most  frequently 
employed.  Where  the  water  comes  from  springs  or  seepage  areas  at 
the  base  of  a  hill  or  is  known  to  be  moving  in  a  definite  direction,  a 
drain  located  either  directly  through  the  spring  or  just  at  the  upper 
edge  of  the  damaged  land  usually  intercepts  the  water  before  it  has 
reached  the  land  it  is  desired  to  improve.  In  an  intercepting  drain 
sometimes  the  variation  of  a  few  feet  one  way  or  the  other  will  mean 
success  or  failure.  Where  springs  are  to  be  drained,  it  is  essential 
that  their  exact  location  be  determined.  A  diligent  use  of  the  soil 
auger  may  reveal  interesting  facts  regarding  subsoil  conditions  in  such 
areas. 

Where  a  regular  system  of  drains,  such  as  the  gridiron  or  herring 
bone,  is  required,  considerable  study  is  often  necessary  in  order  to  plan 
a  lateral  system  to  suit  the  drainage  requirements  and  at  the  same 
time  be  economical.  One  point  to  be  observed  is  the  elimination  of 
all  unnecessary  "double  drained"  areas.  Where  two  drains  join  there 
is  always  an  area  from  which  drainage  water  might  flow  into  either 
drain.  In  Figure  5  the  area  around  the  junction  of  laterals  C  and  B 
with  the  main  drain  may  be  said  to  be  "double  drained."  A  drainage 
system  using  the  minimum  amount  of  tile  consistent  with  efficiency 
is  usually  the  cheapest. 

Depth. — The  depth,  spacing  and  size  of  tile  drains  are  related 
and  interdependent  subjects.  The  proper  depth  for  tile  varies  some- 
what with  the  texture  of  the  soil.  In  sandy  soils  the  depth  may  be 
greater  than  for  clay  since  the  water  moves  more  freely  in  sand  than 
in  clay.  Deep  drains  in  a  clay  soil  will  lower  the  water  table  farther 
than  shallow  ones,  but  it  usually  requires  more  time  after  a  storm  for 
them  to  function.  It  is  well  known  that  drainage  is  more  effective 
and  shows  greater  results  after  two  or  three  years  than  it  does  the 
first.  In  medium  textured  soils,  drains  from  three  and  one-half  to 
four  and  one-half  feet  deep  are  most  satisfactory.    Four  feet  is  prob- 


10 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


-r 

s 


Circ.  304] 


DRAINAGE   ON    THE    FARM 


11 


ably  the  most  efficient  average  depth,  though  a  very  impervious  subsoil 
or  rock  may  make  a  smaller  depth  necessary. 

The  greater  the  depth  of  drained  soil,  the  greater  will  be  root 
penetration,  feeding  area,  available  plant  food  supply  and  drought 
resistance  of  the  crop. 

Spacing. — The  texture  of  the  soil  also  influences  the  spacing  or 
distance  between  laterals.  Since  in  heavy  soils  the  movement  of 
water  is  retarded  by  the  fineness  of  the  soil  particles,  in  such  soils  it 
is  necessary  to  place  drains  closer  together  to  obtain  a  certain  degree 
of  drainage  than  in  a  lighter  soil. 

T      "  T  ;'    T 


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Fig.   6. — The  relation  between   depth   and  spacing  of  tile  and  the  area  affected. 

Other  things  being  equal,  the  greater  the  depth  of  drainage,  the 
wider  the  spacing.  Figure  6  illustrates  this  point.  In  soils  ranging 
from  a  sand  to  a  sandy  loam,  drain  lines  may  be  placed  from  150  to 
300  feet  apart ;  while  in  heavy  silts  and  clays  it  may  be  necessary 
to  place  the  lines  as  close  together  as  thirty  or  forty  feet.  Experience 
with  soils  of  the  same  texture  in  the  same  locality  is  the  best  guide 
for  spacing.  Tile  drains  spaced  as  far  as  150  feet  apart  and  3^ 
feet  deep  have  given  satisfactory  drainage  in  some  instances  in 
California  where  the  soils  are  quite  heavy. 

Grade. — The  more  fall  that  can  be  secured,  other  things  being 
equal,  the  more  rapid  will  be  the  drainage  and  the  smaller  the  tile 
necessary  to  carry  a  given  amount  of  water.  The  necessity  for  accu- 
rately determining  the  grade  on  which  tile  are  to  be  laid  should  be 
emphasized.  This  is  especially  true  when  the  grades  are  fiat.  It  is 
not  so  important  that  any  particular  grade  be  secured,  but  it  is 
important  that  the  grade,  whatever  it  is,  be  known  and  that  the 
tile  be  carefully  laid  to  conform  to  it.  More  than  one  grade  is 
frequently  used  on  long  tile  lines.  This  is  known  as  a  "broken"  grade. 
Whenever  a  grade  is  flattened,  it  must  be  compensated  for  by  an  increase 
in  the  size  of  the  tile.    Whenever  possible,  the  grade  should  be  made 


12  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

steeper  as  the  outlet  is  approached.  Such  a  condition  is  a  reasonable 
assurance  that  particles  of  soil  which  may  enter  the  line  will  be 
carried  on  to  the  outlet  instead  of  settling  in  the  line  with  the  danger 
of  clogging  it.  It  more  often  happens  that  grades  must  be  flattened 
toward  the  outlet,  because  of  the  topography  of  the  land. 

A  fall  of  one  foot  per  thousand  feet,  or  a  grade  of  1/10  of  1  per 
cent,  is  about  as  fiat  as  it  is  advisable  to  use,  although  some  successful 
drains  have  less.  A  grade  of  2  to  5  feet  per  thousand  feet  is  very 
satisfactory  for  tile  lines  and  very  little  difficulty  will  be  encountered 
either  in  construction  or  maintenance  where  this  can  be  secured. 

It  is  sometimes  said  that  one  drain  "draws"  better  than  another 
or  that  the  "draw"  is  of  such  and  such  a  distance.  Actually  drains  do 
not  draw  at  all  in  the  sense  that  they  pull  or  suck  the  water  from 
the  soil.  Underdrains  serve  only  as  collecting  channels  or  outlets 
for  the  water  which  reaches  them  by  gravity.  If  one  field  drains 
farther  back  from  the  lines  of  tile  than  another,  it  is  because  the 
soil  conditions  are  such  that  there  is  a  more  ready  lateral  movement 
of  the  underground  water  to  the  tile  in  one  case  or  that  the  tile  is 
of  insufficient  capacity  to  remove  the  water  as  rapidly  as  it  reaches 
it  in  the  other. 

Discharge  or  Run-off. — The  size  of  tile  necessary  to  drain  a  tract 
of  land  is  based  on  two  considerations,  the  fall  or  grade  on  which 
the  tile  can  be  laid,  and  the  amount  of  water  or  run-off  which  it  is 
necessary  to  carry.  The  grade  can  be  quite  accurately  determined, 
but  the  run-off  is  not  so  easily  obtained.  Drains  are  usually  spoken 
of  as  having  a  capacity  to  remove  in  twenty-four  hours  some  definite 
amount  (%,  ]/2  or  1  inch)  in  depth  of  water  from  the  area  to  be 
drained. 

The  amount  of  water  which  will  reach  the  drains  in  a  given  time 
is  dependent  upon  the  character  of  the  soil,  the  intensity  and  duration 
of  rainfall,  the  size  of  the  area,  and,  to  some  extent,  the  shape  of  the 
area. 

In  clay  soils,  water  reaches  the  tile  more  slowly  than  in  sand; 
therefore,  the  tile  may  be  smaller  in  clay,  although  during  the  season 
as  much  water  may  be  removed  from  one  soil  as  from  the  other.  Open 
drains,  especially  those  designed  to  take  care  of  surface  fiow,  must 
be  built  of  a  size  capable  of  handling  the  maximum  run-off.  At  times 
this  may  amount  to  a  considerable  proportion  of  the  heaviest  rains.  It 
sometimes  happens  in  the  coast  sections  of  California  that  a  steady 
rain  lasting  for  several  days  will  be  followed  by  a  very  heavy  down- 
pour, most  of  which  will  run  off  as  surface  water.  In  normal  years 
this  may  occur  once  or  twice  during  the  winter  season. 


CIRC.  304]  DRAINAGE   ON    THE   FARM  13 

For  tile  drains  the  maximum  twenty-four  hour  rainfall  is  not 
so  important  as  the  maximum  duration  of  any  one  storm.  Long 
continued  rains  which  permit  the  water  to  penetrate  into  the  soil 
rather  than  flow  from  the  surface  usually  cause  the  greatest  discharge 
in  tile  systems.  It  is  seldom  that  underdrains  are  necessary  which 
have  a  larger  twenty-four  hour  carrying  capacity  than  one-half  to 
five-eighths  inch  in  depth  from  the  area  drained,  although  occasionally 
a  run-off  of  1  inch  may  be  obtained.  For  large  areas  the  rate  of  run-off 
at  the  outlet  is  smaller  than  for  small  areas.  The  same  is  true  for 
long,  narrow  areas  as  compared  to  areas  more  nearly  square,  because 
water  from  the  more  distant  sections  does  not  reach  the  outlet  unti] 
after  that  from  nearer  points  has  passed  on. 

The  amount  of  water  to  be  carried  in  a  drainage  system  can  not 
be  exactly  foretold  as  each  case  presents  its  own  local  peculiarities 
and  experience  is  the  best  guide.  An  approximate  estimate  of  the 
discharge  is  necessary  for  a  general  guide,  however,  and  the  figures 
given  will  serve  as  a  basis  for  such  an  estimate. 

Size  of  Tile. — When  the  maximum  amount  of  water  to  be  carried 
has  been  decided  upon  and  the  grade  upon  which  the  drain  can  be 
constructed  is  known,  the  size  of  the  ditch  or  tile  necessary  is  largely 
a  matter  of  computation.  There  are  a  few  general  principles,  how- 
ever, which  do  not  conform  strictly  to  the  mathematical  computation 
of  tile  size. 

It  is  never  advisable  to  use  tile  smaller  than  four  inches  in  diameter, 
even  for  short  laterals;  in  fact,  some  tile  factories  have  discontinued 
the  making  of  drain  tile  less  than  four  inches  in  diameter.  Even 
with  the  greatest  care  irregularities  in  the  grade  or  laying  of  the 
tile  are  sure  to  occur.  A  slight  irregularity  in  a  line  of  small  tile 
has  a  much  more  serious  effect  on  its  efficiency  than  does  a  similar 
irregularity  in  a  line  of  larger  tile. 

Four-  and  six-inch  tile  (preferably  six-inch)  may  ordinarily  be 
used  for  lateral  drains  1000  feet  or  less  in  length.  Six-  and  eight-inch 
tile  may  be  used  for  submains  and  the  upper  ends  of  mains.  Some 
factories  make  the  intermediate  sizes,  five-  and  seven-inch,  which  can 
of  course  be  used  in  their  proper  places. 

Except  for  small  areas,  it  is  not  necessary  to  make  the  capacity  of 
the  main  drain  equal  to  the  combined  capacities  of  the  laterals. 
Lateral  drains  are  seldom  required  to  carry  their  full  capacity;  in 
fact,  a  drain  that  runs  full  for  a  considerable  time  may  safely  be 
considered  too  small. 


14 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


The  difference  between  the  cost  of  a  drainage  system  using  four- 
inch  tile  and  of  one  using  six-inch  tile  for  laterals,  lies  almost  entirely 
in  the  cost  of  the  tile  itself,  which  is  seldom  more  than  30  or  35  per 
cent  of  the  entire  cost  of  the  system.  The  smallest  trench  that  it 
is  practicable  to  dig  by  the  methods  usually  employed  in  California 
will  be  large  enough  for  six  or  even  eight-inch  tile.  There  is  not 
enough  difference  in  weight  between  a  four-inch  and  a  six-inch  tile 


Fig.  7. — Diagram  for  computing  the  size  of  drain  tile  when  certain 
are  known.     (After  Yarnell  and  Woodward.) 


factors 


ClRC.  304]  DRAINAGE   ON    THE   FARM  15 

to  add  materially  to  the  cost  of  laying,  and  the  cost  of  backfilling 
will  be  the  same  in  both  cases.  Furthermore,  incidental  expenses  do 
not  increase  in  direct  proportion  to  the  size  of  tile  used.  To  be  of 
the  highest  efficiency,  the  tile  must  be  of  sufficient  size  to  remove  all 
surplus  water  before  the  crops  are  injured,  even  after  the  heaviest 
rainfall  in  a  continued  wet  period. 

The  diagram  shown  in  figure  7  was  prepared  by  D.  L.  Yarnell  and 
S.  M.  Woodward,  and  used  by  them  in  U.  S.  Department  of  Agricul- 
ture Bulletin  854  as  a  means  of  determining  the  size  of  tile  necessary 
when  certain  facts  are  known.  For  example,  suppose  the  estimated 
run-off  is  %  inch  in  24  hours  from  an  area  of  70  acres  and  the 
available  fall  is  two  feet  per  thousand  (or  .2  foot  per  100),  what  size 
will  the  main  drain  need  to  be?  In  the  third  column  on  the  right 
above  the  title  "R=%"  will  be  found  the  area  "70";  a  horizontal 
line  through  this' point  intersects  a  vertical  line  through  ".2"  found 
on  the  bottom  border  of  the  table  at  a  point  just  below  the  line  sloping 
upward  to  the  right  marked  "  12, ' '  which  represents  the  tile  diameter. 
Thus  a  tile  12  inches  in  diameter  will  be  required.  At  the  same  time 
it  can  be  noted  that  the  discharge  from  this  tile  will  be  slightly  under 
2  cubic  feet  per  second  (left  hand  border),  and  the  velocity  of  flow 
will  be  approximately  2y2  feet  per  second  (line  sloping  upward  to 
the  left).  The  use  of  a  diagram  saves  a  great  deal  of  computation. 
The  method  used  in  computing  the  formula  for  this  diagram  is  fully 
described  in  the  bulletin  referred  to. 

Kinds  of  Tile. — There  are  two  kinds  of  tile  available  for  drainage 
work  in  California,  namely,  clay  tile  and  concrete  tile.  Both  are 
used  extensively,  sometimes  on  the  same  system,  and  both  are  proving 
satisfactory  when  they  have  been  well  made  from  good  material. 

Clay  tile  is  made  in  sizes  varying  from  four  inches  to  twenty-four 
or  thirty  inches  in  diameter,  although  some  factories  do  not  carry 
regular  stocks  in  sizes  greater  than  eighteen  inches.  For  the  large 
sizes,  sewer  pipe  is  sometimes  used.  There  is  no  objection  to  this 
other  than  it  may  be  more  expensive. 

Clay  tile  should  be  straight,  well  burned  and  free  from  defects. 
Soft  or  porous  tile,  either  in  clay  or  concrete  should  be  discarded  as 
defective.  Water  enters  a  tile  line  at  the  joints  between  the  separate 
tile  lengths  and  does  not  pass  through  the  walls  of  the  tile  itself. 
Any  tile  which  is  so  porous  that  water  will  pass  through  the  walls  is 
defective  and  should  be  treated  as  such. 

Concrete  tile  can  usually  be  obtained  in  a  larger  assortment  of 
sizes  than  clay.     Concrete  tile  should  be  true  to  form,  hard,  dense 


16 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


I 
06 


<w      g 


ClRC.  304]  DRAINAGE   ON    THE   FARM  17 

and  thoroughly  cured.  Home-made  tile  is  likely  to  be  inferior  in 
quality  and  its  use  should  be  discouraged  unless  the  builder  has  a 
good  knowledge  of  the  principles  of  concrete  construction.  It  is  safer 
to  purchase  tile  from  a  reliable  manufacturer. 

Reliable  and  established  manufacturers  of  both  clay  and  concrete 
tile  are  thoroughly  familiar  with  the  "Standard  Specifications  for 
Drain  Tile  of  the  American  Society  of  Testing  Materials"  and  make 
a  product  which  they  guarantee  to  meet  those  specifications.  The 
engineer  or  tile  user  should  insist  upon  actual  tests  being  made  if 
there  is  any  doubt  whatever  as  to  its  quality.  Specifications  requiring 
tile  to  be  made  either  of  clay  or  concrete  are  not  in  themselves  assur- 
ance that  a  good  quality  will  be  obtained. 


CONSTRUCTION    OF    TILE    DRAINS 

Before  any  work  is  done,  the  lines  along  which  the  tile  are  to  be 
laid  should  be  staked  out  and  plainly  marked.  This  is  usually  done  by 
setting  a  ' '  guard "  or  "  marker ' '  stake  each  fifty  feet  or  one  hundred 
feet  upon  which  the  distance  from  the  outlet  is  shown.  Close  to 
each  of  these  stakes  another,  known  asa  "  hub "  or  "  grade  stake ' '  is 
driven  so  that  its  top  is  flush  with  the  ground  surface.  (See  figure  8.) 
It  is  from  this  latter  stake  that  measurements  of  depth  or  "cut"  are 
made.  This  stake  must  not  be  disturbed  in  any  way  until  the  tile  is 
laid  and  tested.  The  required  depth  at  each  stake  is  either  recorded 
on  the  marker  stake  or  furnished  the  workman  in  the  form  of  a 
table  or  profile.  The  nearer  edge  of  the  trench  is  laid  off  by  the 
workman  parallel  to  and  about  9  inches  from  the  line  of  stakes.  This 
line  should  be  marked  with  a  stretched  cord  or  by  shovel  marks  on 
the  ground  so  as  to  insure  a  straight  trench. 

Digging  the  Trench. — If  there  is  much  work  to  be  done,  a  trench- 
ing machine  may  be  used.  For  the  type  of  drains  described  in  this 
paper,  the  wheel  type  of  trencher  is  the  most  common,  but  these 
machines  are  too  expensive  for  the  individual  farmer  to  purchase. 
In  some  sections  of  the  state,  drainage  contractors  can  be  found  who 
own  trenchers  and  construct  drains  for  others  at  a  stated  price  per 
foot  or  rod.  A  light  ladder-type  ditcher  can  be  purchased  as  an 
attachment  for  the  Fordson  tractor.  This  machine,  however,  is  rather 
expensive  for  the  small  farmer  unless  he  contemplates  doing  work  for 
others.  Machine  trenching  is  usually  cheaper  than  hand  trenching 
and  has  the  great  advantage  of  being  more  rapid.  In  figure  9  can 
be  seen  a  wheel-type  excavator  at  work. 


18 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


Fig.  9. — Drainage  contractors  use  excavators  which  dig  trenches  rapidly  and 
accurately  and  usually  at  a  less  cost  than  the  work  can  be  done  by  hand. 

For  hand  dug  trenches,  one  of  the  tile  spades  shown  in  figure  10 
is  the  most  satisfactory  where  the  ground  is  moist.  This  tool,  however, 
is  not  very  common  in  California.  Often  work  is  done  during  the 
dry  part  of  the  year  when  it  is  necessary  to  use  a  pick  to  loosen  the 
soil.  Work  done  at  this  time,  however,  is  more  expensive  than  when 
done  at  a  time  when  the  more  convenient  tools  can  be  used.  Digging 
should  always  start  at  the  outlet  so  that  any  water  that  is  encountered 


Fig.  10. — Tools  used  in  constructing  tile  drains  by  hand. 


Circ.  304] 


DRAINAGE    ON    THE    FARM 


19 


can  drain  away.  Even  when  the  ground  is  dry  at  the  time  of  digging 
the  trench,  it  is  best  to  begin  at  the  outlet.  The  trench,  unless  dug 
by  machinery,  should  be  finished  to  within  an  inch  or  so  of  the  bottom 
before  the  grade  line  is  set.  With  machine  dug  trenches  a  skilled 
operator  can  dig  very  close  to  grade  at  a  single  operation. 

Establishing  Grade. — It  is  very  essential  that  tile  be  laid  true  to  the 
established  grade.  When  tile  drains  become  clogged  or  silted  up  it  is 
very  probable  that  they  were  not  laid  absolutely  true  to  grade. 


Fig.  11. — Measuring  down  from  an  overhead  cord  to  make  sure  that  the 
completed  trench  is  everywhere  seven  feet  from  the  line.  (Courtesy  of  Inter- 
national  Harvester   Co.) 


An  easy  method  of  determining  the  true  grade  at  all  points  along 
the  line  is  to  stretch  a  light  stout  cord  on  cross-bars  directly  over  the 
trench  and  at  some  chosen  distance,  say  7  feet  above  the  bottom. 
The  cross-bars  are  located  at  the  stakes  which  have  been  set  by  the 
engineer.  The  bars  are  placed  at  a  distance  above  the  grade  stake 
equal  to  the  difference  between  7  and  the  "cut"  or  depth  of  trench 
at  that  point.  A  cord  stretched  across  a  number  of  bars  so  placed 
will  everywhere  along  its  length  be  7  feet  above  the  true  bottom  of 
the  trench,  which  can  easily  be  determined  by  measuring  down  from 
the  cord  at  any  point  (see  figure  11).    Care  should  be  taken  to  see 


20 


UNIVERSITY    OF    CALIFORNIA- — EXPERIMENT    STATION 


that  the  cord  is  supported  at  intervals  to  prevent  its  sagging.  When 
the  grade  cord  is  set  the  almost  completed  trench  can  be  finished  with 
a  shovel  and  tile  scoop. 

Laying  Tile. — It  is  presumed  that  the  tile  has  already  been  dis- 
tributed along  the  line  within  easy  reach  from  the  trench.  Small 
tile  can  be  placed  from  the  bank  with  a  tile  hook,  as  shown  in  figure  12. 
They  should  be  placed  end  to  end  as  closely  as  they  will  lie  in  the 
trench.  Tiles  will  occasionally  be  found  whose  ends  are  not  exactly 
square,  but  by  turning  them  slightly  they  can  be  made  to  fit  closely. 


t*H 


"V* 


Fig.  12. — Laying  small  tile  with  a  tile  hook  from  the  top  of  the  trench. 
(Courtesy  of  International  Harvester  Co.) 

Tile  larger  than  about  8  inches  in  diameter  are  placed  by  hand 
from  the  bottom  of  the  trench,  as  they  are  too  heavy  to  conveniently 
handle  with  the  tile  hook,  and  those  over  18  inches  in  diameter  are 
lowered  into  the  trench  with  a  block  and  tackle. 

Tile  should  receive  a  final  inspection  just  before  laying,  as  some 
may  be  damaged  after  they  are  brought  to  the  field.  A  single  tile 
that  fails  after  being  placed  may  destroy  the  usefulness  of  the  entire 
line  above  it.  It  is  better  to  discard  a  good  tile  occasionally  than  to 
put  in  a  single  poor  one. 

As  soon  as  the  tile  is  in  position,  a  little  earth  cut  from  the  side 
of  the  trench  will  prevent  its  rolling  out  of  line.  After  each  50  or  100 
feet  of  tile  is  laid  and  at  the  end  of  each  day's  work,  the  tile  laid 


CIRC.  304]  DRAINAGE   ON    THE   FARM  21 

should  be  covered  with  earth  to  a  depth  of  three  or  four  inches 
so  as  to  protect  it  from  injury  or  dislocation  by  falling  stones  or 
chunks  of  earth.  Sometimes  in  heavy  soil,  the  first  backfill  or  ' '  blind- 
ing, ' '  as  it  is  called,  is  done  with  soil  from  the  surface  containing  some 
sod  or  grass.  A  little  straw,  gravel,  or  rock  may  be  used  in  order  to 
keep  heavy  clay  from  packing  too  closely  about  the  tile.  If  quick- 
sand is  encountered,  these  substances  may  be  effectively  used  to 
prevent  its  entrance  into  the  tile.  These  precautions,  however,  are 
necessary  only  in  unusual  circumstances. 


Fig.  13. — Backfilling  a  tile  trench  with  slip  scraper. 

Backfilling. — If  the  tile  are  to  be  inspected  by  the  engineer,  such 
inspection  should  be  done  just  before  they  are  covered.  The  filling 
of  the  trench  can  be  accomplished  in  several  ways.  In  places  where  the 
work  is  crowded,  such  as  in  an  orchard  or  around  buildings,  the  back- 
filling can  best  be  done  by  hand  with  shovels.  In  the  open  field  the 
soil  is  usually  plowed  into  the  trench.  A  long  doubletree  is  provided 
so  that  one  horse  or  one  team  is  on  each  side  of  the  trench.  This 
method  requires  from  two  to  three  men  and  steady  teams.  Small 
slip  or  four-horse  Fresno  scrapers  are  sometimes  used,  in  which  case 
the  team  works  on  the  opposite  side  of  the  trench  from  the  scraper. 
(See  figure  13.)  Power  operated  backfillers  are  too  expensive  for  the 
average  farmer  to  own,  but  they  are  very  desirable  for  the  drainage 
contractor. 

All  of  the  earth  excavated  from  the  trench  should  be  replaced; 
otherwise  there  will  be  a  depression  along  the  line  when  the  soil  settles. 


22 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


BOX    DRAINS 

Box  drains  may  be  used  when  lumber  can  be  secured  at  a  reason- 
able price  and  tile  is  very  expensive.  The  installation  of  box  drains 
is  similar  in  every  respect  to  that  of  tile,  and  the  same  care  should 
be  used.  (See  figure  14).  Redwood  lumber  is  much  more  durable 
than  pine  or  fir  and  should  be  used  for  all  underground  work  in 


Fig.   14. — Box  drains  in  place  and  ready   for   backfilling  in  a   Placer  County 
pear  orchard. 

b  c 


Fig.  15. — Types  of  lumber  box  drains. 

California.  It  is  reasonable  to  expect  redwood  boxes  to  last  for  ten 
or  twelve  years;  if  kept  wet  during  the  entire  year,  they  will  last 
much  longer.  In  all  cases,  however,  where  lumber  is  used  for  under- 
ground work  its  life  can  be  lengthened  by  treating  with  creosote. 

Simple  forms  of  boxes  are  shown  in  figure  15.  The  lumber  for  the 
smaller  box  (a)  should  run  lengthwise.  The  sections  may  be  from 
twelve  to  sixteen  feet  long  if  the  trench  will  remain  open  for  that 


Circ.  304] 


DRAINAGE    ON    THE    FARM 


23 


distance.  The  top  is  nailed  tightly  to  the  sides,  but  the  bottom 
is  held  away  from  the  sides  by  short  pieces  of  lath  placed  at  intervals 
of  three  or  four  feet.  In  boxes  with  interior  dimensions  greater  than 
eight  inches  square,  two-inch  lumber  should  be  used  and  the  top 
and  bottom  put  on  crosswise  (b).  In  large  boxes  for  main  drains,  the 
lumber  for  the  top,  bottom,  and  sides  should  all  run  crosswise.  The 
bottom  pieces  should  be  separated  so  that  when  the  lumber  becomes 
wet  and  swells  it  will  not  close  all  openings  for  the  water.  The  use 
of  box  drains  without  bottoms  is  not  advisable,  as  the  water  is  likely 
to  undermine  the  sides  and  cause  the  box  to  settle.  Furthermore,  any 
roughness  of  the  bottom  of  the  trench  will  reduce  the  capacity  of 
the  drain. 


Fig.  16. — Surface  inlets  with  screens. 


STRUCTURES 

Surface  water  should  not  be  allowed  to  enter  directly  into  a  tile  line 
unless  some  provision  is  made  to  exclude  sand,  dirt,  sticks,  and  other 
rubbish.  Figure  16  shows  two  methods  of  screening  surface  water 
before  it  enters  a  drain.  One  consists  of  a  concrete  box  with  an  open 
bottom  resting  on  a  bed  of  stones  which  covers  the  tile.  Water  enters 
the  box  near  the  top  through  wire  screens.  The  wire  screens  keep 
large  particles,  such  as  leaves  and  sticks,  from  entering  the  box  and 
the  stone  filter  removes  sand  and  finer  particles  from  the  water  before 
it  enters  the  tile  line.  The  other  device  is  made  from  sewer  pipe 
through  which  the  water  passes  to  enter  the  line.  A  heavy  iron 
grating  covered  with  small  stones  will  prevent  the  entrance  of  any- 
thing, except  the  water.  If  there  is  a  considerable  quantity  of  water, 
the  stone  filter  should  extend  over  a  greater  length  of  tile  than  shown. 


24 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


The  types  of  screen  shown  in  this  figure  admit  water  readily  to 
the  tile  line,  but  when  placed  in  open  fields  are  an  obstruction  to 
cultivation. 

It  is  good  practice  to  install  silt  boxes  at  intervals  along  a  tile  drain 
to  catch  and  retain  any  silt  that  may  enter  the  line.     These  boxes 


So//\.       s~2*6*3'-3- 


Fig.  17. — Combination  manhole  and  silt -box  w 


ith  cover.    (After  D.  G.  Miller.) 


may  be  made  of  lumber,  concrete  or  brick.  A  very  satisfactory  com- 
bination silt-box,  manhole  and  observation  well  of  lumber  is  shown  in 
figure  17.  It  is  inadvisable  to  construct  silt  boxes  so  small  that  they 
can  not  be  readily  entered  and  cleaned.  They  should  be  placed  at 
points  where  the  grade  changes  to  a  natter  one,  or  where  there  are 
abrupt  changes  in  the  direction  of  the  line.  The  junction  of  two  lines 
is  easily  effected  through  such  a  box,  although  in  the  gridiron  or 


Circ.  304] 


DRAINAGE    ON    THE    FARM 


25 


herring  bone  system  of  drains  it  would  not  be  advisable  to  place  a  box 
at  each  junction. 

The  outlet  of  a  tile  drainage  system,  unless  very  favorably  located, 
should  be  protected  by  some  device  which  will  prevent  the  tile  from 
washing  out  or  becoming  injured  or  displaced.  The  outlet  protection 
may  be  made  of  lumber,  stone,  brick,  or  concerte,  the  design  depending 
upon  the  conditions  which  exist  at  the  outlet.  In  any  case  care  should 
be  taken  to  secure  a  good  foundation  and  anchorage  so  that  the 
structure  will  not  be  undermined.  Figure  18  shows  an  outlet  pro- 
tection for  small  tile,  and  the  illustration  on  the  front  page  of  this 
circular  shows  a  more  elaborate  outlet  for  a  large  main  drain.  The 
construction  material  used  in  making  silt  wells  may  also  be  used  for 
outlet  protections. 


Fig.   18. — Timber  outlet  protection  for  small   tile. 


MAINTENANCE    OF    TILE    DRAINS 

Properly  installed  tile  drains  require  very  little  maintenance.  The 
silt  boxes  should  be  inspected  frequently  during  the  first  year  and  at 
regular  intervals  thereafter,  and  should  be  kept  free  from  silt.  The 
covers  of  silt  boxes  should  be  kept  closed  and  locked  at  all  times. 
(See  figure  19.)  Tumble  weeds,  rabbits,  and  squirrels  may  enter 
the  silt  boxes  and  obstruct  the  tile  lines  unless  this  precaution  is 
observed. 

Soil  will  not  seal  the  joints  and  prevent  the  entrance  of  water  into 
the  tile  lines  under  ordinary  conditions.  There  need  be  but  little 
fear  of  the  roots  of  fruit  trees  growing  into  a  tile  line  unless  the  tile 
carries  water  when  the  surrounding  soil  is  dry.     Such  a  condition 


26  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

would  exist  when  the  drain  taps  a  spring  which  flows  long  after  the 
surrounding  area  has  become  dry.  Cottonwood  and  willow  trees, 
however,  should  not  be  allowed  to  grow  within  fifty  feet  of  a  tile  line, 
as  they  are  water  loving  trees  and  frequently  cause  serious  trouble. 

Should  a  tile  line  become  obstructed  in  any  way,  silt  boxes  located 
at  frequent  intervals  will  aid  materially  in  locating  the  obstruction. 
A  number  of  devices  have  been  developed  for  cleaning  sewers  which 
can  be  used  for  drain  tile.  These  may  also  be  found  useful  during 
construction,  especially  if  the  tile  is  laid  in  a  wet,  muddy  trench. 


Fig  19. — A  manhole  made   from  large  concrete  tile  and  having  a  metal 
cover  securely  fastened  with  a  heavy  chain  and  padlock. 

The  most  common  form  of  tile  cleaner  is  one  whose  several  sections 
can  be  joined  together  when  the  rods  are  held  at  right  angles,  but 
can  not  be  unhooked  when  extended.  These  rods  may  be  used  with 
or  without  any  of  the  various  attachments  such  as  an  auger,  wire 
brush,  hoe,  or  spiral  cutter.  A  very  simple  brush  can  be  made  by 
wrapping  a  piece  of  leather  belting  around  a  cylindrical  rod,  the 
belting  first  having  been  driven  full  of  wire  nails  of  such  a  length  that 
the  completed  brush  will  not  quite  fill  the  tile.  Care  must  be  exercised 
not  to  use  fixtures  that  may  become  detached  or  will  catch  on  the  tile. 
Two  hundred  and  fifty  feet  or  more  of  rod  can  be  operated  in  a 
straight  tile  line. 


Circ.  304] 


DRAINAGE    ON    THE    FARM 


27 


COST   OF    DRAINAGE 

The  matter  of  cost  is  probably  the  most  important  item  in  drain- 
age ;  upon  this  depends  the  feasibility  of  any  undertaking.  The 
engineer  who  has  planned  a  system  should  be  able  to  estimate  the  cost 
of  it  very  closely.  Unless  the  details  of  construction  are  known,  how- 
ever, only  general  and  approximate  cost  data  can  be  given. 

There  are  only  a  very  few  factories  on  the  Pacific  Coast  which 
manufacture  clay  drain  tile  exclusively,  most  of  it  being  made  to 
order  or  as  a  side  line  by  clay  products  factories.  Cement  tile  plants 
are  more  numerous,  as  practically  the  same  equipment  is  used  for 
the  manufacture  of  drain  tile  as  for  irrigation  pipe. 

TABLE  1 


Clay 

Concrete 

Size 

Price  per  foot 

Weight  per  foot 

Price  per  foot 

Weight  per  foot 

4 

5c  to  8c 

7 

5c  to  8c 

9 

6 

8c  to  13c 

ny2 

8c  to  13c 

18 

8 

14c  to  22c 

193^ 

14c  to  18c 

27 

10 

20c  to  30c 

32 

18c  to  26c 

36 

12 

28c  to  38c 

40 

25c  to  35c 

42 

14 

35c  to  51c 

50 

33c  to  42c 

64 

16 

45c  to  60c 

60 

40c  to  55c 

85 

18 

60c  to  90c 

100 

65c  to  75c 

102 

20 

90c  to  $1.10 

138 

75c  to  90c 

120 

22 

$1.25  to  SI.  55 

150 

90c  to  $1.10 

145 

24 

$1.60  to  $1.90 

165 

$1.10  to  $1.25 

170 

26 

$2.00  to  $2.50 

200 

$1.50  to  $1.75 

210 

28 

$2.  50  to  $3. 00 

235 

$1.90  to  $2. 50 

250 

30 

$3. 00  to  $3.  50 

265 

$2.50  to  $3  00 

277 

Tile  are  sold  by  the  foot  or  the  1000  feet,  with  discounts  on  car 
lots.  Tile,  both  clay  and  concrete,  are  higher  priced  in  all  of  the 
western  states  than  in  the  East  or  Middle  West.  Table  1  may  be  used 
as  a  general  guide  to  the  price  of  drain  tile  at  the  factory,  and  the 
weights  given  may  be  used  as  a  basis  for  figuring  freight  charges. 

Both  price  and  weight,  however,  may  vary  from  the  figures  given. 
Frequently  prices  are  quoted  on  pipe  delivered  at  the  rail  point 
nearest  the  consumer  or  along  the  trench  by  truck. 

Excavation  of  hand  dug  trenches  will  cost,  at  the  present  price 
of  common  labor,  from  40  to  60  cents  an  hour,  from  10  to  20  cents  a 
lineal  foot  for  depths  of  from  three  to  five  feet  and  width  sufficient 


28  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

for  8-inch  tile.  The  cost  varies  somewhat  with  the  season,  the  con- 
dition of  the  soil  and  the  amount  of  labor  available. 

Machine-dug  trenches  under  favorable  conditions  will  cost  about 
one-half  as  much  as  hand-dug  trenches. 

Laying  and  backfilling  will  vary  somewhat,  but  for  the  smaller 
sizes  of  tile  will  probably  cost  from  3  to  5  cents  a  lineal  foot.  This 
will  bring  the  cost  of  a  completed  6-inch  drain  to  about  30  cents  a 
foot.  It  may  be  roughly  estimated  that  the  cost  of  tile  is  from  30  to  40 
per  cent  of  the  cost  of  the  completed  system. 


DRAINAGE    OF    PEAT    SOILS 

Peat  soils,  such  as  are  frequently  found  in  small  areas  throughout 
the  coast  region  and  in  the  foothills  of  the  Sierras,  often  require  a 
different  system  of  drainage  than  do  other  soils.  Peat  is  formed  by 
the  decaying  vegetation  that  grows  in  the  presence  of  an  abundant 
water  supply.  It  is  often  found  surrounding  or  just  below  a  spring 
or  permanent  seepage  area.  For  the  drainage  of  these  soils,  it  is 
essential  that  the  source  of  the  water  be  found  and  the  water  inter- 
cepted. 

Peat  shrinks  and  settles  markedly  when  drained,  and  tile  are  likely 
to  become  misplaced  unless  some  precautions  are  taken  to  prevent  it. 
If  the  peat  is  not  too  deep,  the  drains  may  be  laid  directly  on  the 
subsoil.  If,  however,  the  peat  is  too  deep  for  this,  it  may  be  necessary 
to  support  the  tile  on  a  cradle  made  of  lumber.  Where  the  depth 
of  the  peat  is  irregular,  a  cradle  is  sometimes  used  to  support  that 
part  of  the  drain  which  does  not  rest  on  solid  subsoil.  The  cradle 
consists  of  two  boards,  usually  of  1  in.  by  3  in.  material,  laid  parallel 
and  about  3  inches  apart.  These  are  held  together  by  cleats  on  the 
under  side ;  sometimes  the  whole  cradle  is  nailed  to  posts  driven  in 
the  bottom  of  the  trench. 

Peat  soils  can  not  usually  be  drained  as  deeply  as  others,  because 
the  capillary  rise  of  water  through  them  is  very  low,  and,  unless 
irrigation  is  available  or  the  water  table  is  relatively  close  to  the 
surface,  crops  may  suffer  from  drought.  Peat  land  crops  are  of 
necessity,  therefore,  shallow-rooted. 


ClRC.  304]  DRAINAGE   ON    THE   FARM  29 


DRAINAGE    OF    TIDAL    MARSHES 

In  the  drainage  of  tidal  marshes,  it  is  usually  necessary  to  protect 
the  land  from  tidal  inundation  by  means  of  levees,  and  the  drainage 
water  is  discharged  through  tide  gates  or  pumping  plants.  The 
designing  of  these  are,  however,  not  within  the  scope  of  this  circular. 
Most  drainage  for  reclaimed  tidal  marshes  in  California  has  been 
of  the  open  ditch  type,  but  the  use  of  tile  may  prove  to  be  more 
efficient. 

The  soils  are  usually  very  heavy  textured  and  contain  large 
quantities  of  salt.  Drains  from  3%  to  4  feet  in  depth  and  spaced 
from  50  to  100  feet  apart  are  proving  satisfactory.  It  is  necessary 
to  keep  the  outlet  drains,  which  are  usually  open  ditches  leading  to 
the  gates  or  pumps,  as  nearly  empty  as  possible,  so  that  the  lateral 
drains  will  operate  freely.  Except  for  seepage  through  the  levees, 
which  is  collected  in  an  open  drain  just  inside  the  levee,  the  run-off 
for  tidal  marshes  is  about  the  same  as  from  similar-sized  areas  of 
adjacent  uplands.  Tidal  marshes  usually  have  no  natural  fall,  and 
the  grades  for  tile  must  be  made  by  placing  them  shallower  at  the 
upper  end  than  at  the  lower.  Care  should  be  taken  to  have  the 
upper  ends  deep  enough  to  provide  adequate  drainage,  even  though 
it  may  mean  that  the  lower  ends  are  deeper  than  would  otherwise  be 
necessary. 

VERTICAL    DRAINAGE 

By  vertical  drainage  is  meant  the  passing  of  drainage  water 
vertically  through  the  soil  into  a  porous  bed  of  sand  or  gravel  beneath ; 
it  is  effected  by  means  of  wells  or  pipes  extending  into  the  porous 
substratum.  Vertical  drainage  is  feasible  only  when  the  surface  soil 
is  underlaid  by  an  impervious  layer  of  clay  or  hardpan,  beneath 
which  is  a  porous  layer  of  sand  or  gravel,  which  contains  no  water, 
or  affords  a  channel  through  which  the  water  may  escape.  Such  a 
set  of  conditions  is  rarely  found.  The  hardpan  is  usually  underlaid 
by  a  non-porous  subsoil  filled  with  water  which  does  not  flow  away. 
It  would  be  useless  to  attempt  vertical  drainage  if  the  subsoil  were  not 
porous,  even  though  it  were  dry,  because  its  water  holding  capacity 
would  soon  be  reached,  and  the  drain  would  then  become  inoperative. 

Vertical  drainage,  where  practicable,  may  be  accomplished  by 
boring  an  8  or  10  inch  hole  well  into  the  porous  stratum  and  lining 
this  hole  with  ordinary  drain  tiles  set  one  on  top  of  another.     The 


30  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

top  must  be  securer/  covered  and  screened  so  as  to  prevent  the 
entrance  of  silt  or  trash  into  the  drain.  Another  method  of  accom- 
plishing vertical  drainage  where  the  impervious  layer  is  hardpan  is 
to  break  up  the  impervious  stratum  with  dynamite.  If  this  method 
were  used  on  a  layer  of  clay  the  clay  would  have  a  tendency  to  puddle 
back  into  an  impervious  layer,  and  instead  of  breaking  and  shattering, 
would  pack  and  burn  at  the  point  of  the  explosion. 

Every  instance  of  contemplated  vertical  drainage  should  be  thor- 
oughly examined,  as  subsoil  conditions  will  almost  always  be  found 
unsuited  to  this  type  of  drainage. 


CO-OPERATION    IN    DRAINAGE 

It  is  seldom  that  a  farmer  can  install  an  extended  and  compre- 
hensive drainage  system  without  cooperating  to  some  extent  with  other 
landowners.  Cooperation  is  often  necessary  to  obtain  an  outlet.  The 
right  to  drain  land  should  not  be  abridged  by  the  prejudices  of  an 
adjacent  landowner.  The  rights  of  those  owning  lower  land  which 
must  be  crossed  by  the  drains  of  another  must  not  be  ignored,  how- 
ever, and  if  any  injury  whatever  is  sustained  it  should  be  paid  for.  As 
a  matter  of  fact,  a  drain  usually  benefits  the  lower  land  by  crossing 
it,  and  some  arrangement  should  therefore  be  made  whereby  the  cost 
of  such  a  drain  will  be  borne  by  both  parties.  These  matters  should 
be  amicably  settled  before  work  is  begun. 

Where  there  are  a  number  of  persons  interested  in  any  particular 
drain  or  system  of  drains  better  cooperation  can  be  secured  through 
the  organization  of  a  drainage  district,  This  provides  a  means  of 
securing  a  comprehensive  and  well  planned  system,  of  financing,  and 
of  making  and  collecting  assessments.  California  is  now  adequately 
supplied  with  statutes  covering  this  subject.  The  organization  of  a 
drainage  district  should  not  be  attempted  without  the  assistance  and 
advice  of  an  attorney  to  make  certain  that  the  proper  procedure  is 
followed. 


STATION  PUBLICATIONS  AVAILABLE  FOR  FREE  DISTRIBUTION 


BULLETINS 


No. 

253.   Irrigation   and   Soil   Conditions   in  the 
Sierra   Nevada   Foothills,    California. 

261.  Melaxuma    of    the    Walnut,     "Juglans 

regia." 

262.  Citrus   Diseases   of   Florida   and   Cuba 

Compared  with  Those  of  California. 

263.  Size   Grades   for  Ripe   Olives. 

268.   Growing  and  Grafting  Olive  Seedlings. 
273.   Preliminary  Report  on  Kearney  Vine- 
yard  Experimental   Drain. 

275.  The     Cultivation     of     Belladonna     in 

California. 

276.  The  Pomegranate. 

277.  Sudan   Grass. 

278.  Grain    Sorghums. 

279.  Irrigation   of   Rice   in   California. 

280.  Irrigation    of    Alfalfa     in    the    Sacra- 

mento Valley. 
283.   The   Olive   Insects  of  California. 
285.   The  Milk   Goat   in   California. 
294.   Bean   Culture  in    California. 
304.   A   Study  of  the  Effects  of   Freezes  on 

Citrus    in    California. 
310.   Plum    Pollination. 

312.  Mariout   Barley. 

313.  Pruning      Young      Deciduous      Fruit 

Trees. 
319.   Caprifigs    and    Caprification. 

324.  Storage  of   Perishable  Fruit   at  Freez- 

ing Temperatures. 

325.  Rice     Irrigation     Measurements      and 

Experiments    in    Sacramento   Valley, 

1914-1919. 
328.   Prune    Growing   in    California. 
331.   Phylloxera-Resistant    Stocks. 

334.  Preliminary    Volume    Tables    for    Sec- 

ond-Growth  Redwood. 

335.  Cocoanut    Meal    as    a    Feed    for    Dairy 

Cows    and    Other   Livestock. 

339.  The    Relative    Cost    of    Making    Logs 

from   Small   and  Large  Timber. 

340.  Control     of     the     Pocket     Gopher     in 

California. 

343.  Cheese    Pests    and    Their    Control. 

344.  Cold    Storage    as    an   Aid   to    the    Mar- 

keting of  Plums. 

346.  Almond    Pollination. 

347.  The  Control  of  Red  Spiders  in  Decid- 

uous Orchards. 

348.  Pruning  Young  Olive  Trees. 

349.  A     Study    of    Sidedraft    and    Tractor 

Hitches. 

350.  Agriculture      in      Cut-over      Redwood 

Lands. 

352.  Further  Experiments  in  Plum  Pollina- 

tion. 

353.  Bovine   Infectious   Abortion. 

354.  Results  of  Rice  Experiments  in   1922. 

357.  A     Self-mixing    Dusting    Machine    for 

Applying      Dry       Insecticides       and 
Fungicides. 

358.  Black    Measles,     Water    Berries,     and 

Related  Vine  Troubles. 

359.  Fruit   Beverage    Investigations. 

361.  Preliminary    Yield    Tables    for    Second 

Growth   Redwood. 

362.  Dust  and  the  Tractor  Engine. 


No. 
363. 

364. 

365. 
366. 

367. 

368. 

369. 

370. 
371. 

372. 

373. 
374. 

375. 

376. 

377. 
379. 
380. 

381. 

382. 

383. 

384. 


385. 
386. 

387. 
388. 

389. 
390. 

391. 

392. 
394. 

395. 
396. 

397. 

398. 
399. 


400. 


The  Pruning  of  Citrus  Trees  in  Cali- 
fornia. 

Fungicidal  Dusts  for  the  Control  of 
Bunt. 

Avocado  Culture  in   California. 

Turkish  Tobacco  Culture,  Curing  and 
Marketing. 

Methods  of  Harvesting  and  Irrigation 
in   Relation   of   Mouldy  Walnuts. 

Bacterial  Decomposition  of  Olives  dur- 
ing  Pickling. 

Comparison  of  Woods  for  Butter 
Boxes. 

Browning  of  Yellow  Newtown  Apples. 

The  Relative  Cost  of  Yarding  Small 
and   Large   Timber. 

The  Cost  of  Producing  Market  Milk  and 
Butterfat  on  246  California  Dairies. 

Pear   Pollination. 

A  Survey  of  Orchard  Practices  in  the 
Citrus  Industry  of  Southern  Cali- 
fornia. 

Results  of  Rice  Experiments  at  Cor- 
tena,    1923. 

Sun-Drying  and  Dehydration  of  Wal- 
nuts. 

The   Cold   Storage   of   Pears. 

Walnut    Culture    in   California. 

Growth  of  Eucalyptus  in  California 
Plantations. 

.Growing  and  Handling  Asparagus 
Crowns. 

Pumping  for  Drainage  in  the  San 
Joaquin    Valley,    California. 

Monilia  Blossom  Blight  (Brown  Rot) 
of  Apricot. 

A  Study  of  the  Relative  Values  of  Cer- 
tain Succulent  Feeds  and  Alfalfa 
Meal  as  Sources  of  Vitamin  A  for 
Poultry. 

Pollination    of    the    Sweet    Cherry. 

Pruning  Bearing  Deciduous  Fruit 
Trees. 

Fig   Smut. 

The  Principles  and  Practice  of  Sun- 
drying  Fruit. 

Berseem  or  Egyptian   Clover. 

Harvesting  and  Packing  Grapes  in 
California. 

Machines  for  Coating  Seed  Wheat  with 
Copper    Carbonate    Dust. 

Fruit    Juice    Concentrates. 

Cereal  Hay  Production  in  California. 
Feeding  Trials  with  Cereal  Hay. 

Bark   Diseases   of   Citrus  Trees. 

The  Mat  Bean  (Phaseolus  aconilifo- 
lius). 

Manufacture  of  Roquefort  Type  Cheese 
from   Goat's   Milk. 

Orchard  Heating  in  California. 

The  Blackberry  Mite,  the  Cause  of 
Redberry  Disease  of  the  Himalaya 
Blackberry,    and   its   Control. 

The  Utilization  of  Surplus  Plums. 


No. 

87. 
113. 
117. 

127. 
129. 
136. 


CIRCULARS 
No. 


Alfalfa. 

Correspondence  Courses  in  Agriculture. 

The    Selection    and    Cost    of    a    Small 

Pumping  Plant. 
House    Fumigation. 
The  Control  of  Citrus   Insects. 
Melilotus    indica    as    a    Green-Manure 

Crop  for  California. 


144.   Oidium    or    Powdery    Mildew    of    the 
Vine. 

151.  Feeding  and  Management  of  Hogs. 

152.  Some  Observations  on  the  Bulk  Hand- 

ling of    Grain   in    California. 

154.  Irrigation  Practice  in   Growing   Small 

Fruit    in    California. 

155.  Bovine  Tuberculosis. 


CIRCULARS— (Continued) 


No. 
157. 

160. 
164. 
166. 
167. 
170. 

173. 

178. 
179. 

184. 
190. 
199. 
202. 

203. 
209. 
210. 
212. 
214. 

215. 
217. 

220. 
228. 
230. 

231. 
232. 

233. 
234. 

235. 

236. 


238. 
239. 

240. 

241. 

242. 
243. 

244. 
245. 
247. 
248. 

249. 
250. 

251. 


252. 
253. 
254. 

255. 


Control  of  the  Pear  Scab. 

Lettuce  Growing  in  California. 

Small   Fruit  Culture  in   California. 

The   County   Farm  Bureau. 

Feeding    Stuffs    of   Minor    Importance. 

Fertilizing  California  Soils  for  the 
1918   Crop. 

The  Construction  of  the  Wood-Hoop 
Silo. 

The   Packing  of  Apples   in   California. 

Factors  of  Importance  in  Producing 
Milk   of   Low   Bacterial   Count. 

A   Flock   of   Sheep   on  the   Farm. 

Agriculture  Clubs   in   California. 

Onion    Growing   in    California. 

County  Organizations  for  Rural  Fire 
Control. 

Peat   as   a   Manure    Substitute. 

The  Function  of  the   Farm   Bureaii. 

Suggestions  to  the  Settler  in  California. 

Salvaging    Rain-Damaged    Prunes. 

Seed  Treatment  for  the  Prevention  of 
Cereal  Smuts. 

Feeding  Dairy  Cows  in  California. 

Methods  for  Marketing  Vegetables  in 
California. 

Unfermented    Fruit   Juices. 

Vineyard  Irrigation  in  Arid  Climates. 

Testing  Milk,  Cream,  and  Skim  Milk 
for   Butterfat. 

The    Home    Vineyard. 

Harvesting  and  Handling  California 
Cherries    for    Eastern    Shipment. 

Artificial    Incubation. 

Winter  Injury  to  Young  Walnut  Trees 
during  1921-22. 

Soil  Analysis  and  Soil  and  Plant. 
Inter-relations. 

The  Common  Hawks  and  Owls  of 
California  from  the  Standpoint  of 
the  Rancher. 

Directions  for  the  Tanning  and  Dress- 
ing of  Furs. 

The  Apricot  in   California. 

Harvesting  and  Handling  Apricots 
and  Plums  for  Eastern   Shipment. 

Harvesting  and  Handling  Pears  for 
Eastern    Shipment. 

Harvesting  and  Handling  Peaches  for 
Eastern    Shipment. 

Poultry  Feeding. 

Marmalade  Juice  and  Jelly  Juice  from 
Citrus  Fruits. 

Central  Wire  Bracing  for  Fruit  Trees. 

Vine    Pruning    Systems. 

Colonization    and    Rural    Development. 

Some  Common  Errors  in  Vine  Prun- 
ing and  Their  Remedies. 

Replacing  Missing  Vines. 

Measurement  of  Irrigation  Water  on 
the   Farm. 

Recommendations  Concerning  the  Com- 
mon Diseases  and  Parasites  of 
Poultry   in   California. 

Supports  for  Vines. 

Vineyard  Plans. 

The  Use  of  Artificial  Light  to  Increase 
Winter    Egg    Production. 

Leguminous  Plants  as  Organic  Fertil- 
izer   in    California    Agriculture. 


No. 

256.  The   Control   of  Wild   Morning   Glory. 

257.  The   Small-Seeded  Horse  Bean. 

258.  Thinning   Deciduous   Fruits. 

259.  Pear   By-products. 

260.  A  Selected  List  of  References  Relating 

to  Irrigation  in  California. 

261.  Sewing  Grain   Sacks. 

262.  Cabbage   Growing   in   California. 

263.  Tomato   Production  in  California. 

264.  Preliminary      Essentials      to      Bovine 

Tuberculosis  Control. 

265.  Plant   Disease   and   Pest   Control. 

266.  Analyzing     the     Citrus     Orchard     by 

Means   of    Simple   Tree    Records. 

267.  The   Tendency   of   Tractors  to   Rise  in 

Front ;    Causes   and   Remedies. 

268.  Inexpensive  Labor-saving  Poultry  Ap- 

pliances. 

269.  An   Orchard  Brush  Burner. 

270.  A  Farm  Septic  Tank. 

271.  Brooding    Chicks    Artificially. 

272.  California  Farm  Tenancy  and  Methods 

of  Leasing. 

273.  Saving  the   Gophered   Citrus   Tree. 

2  74.   Fusarium  Wilt  of  Tomato  and  its  Con- 
trol by  Means  of  Resistant  Varieties. 

275.  Marketable        California        Decorative 

Greens. 

276.  Home   Canning. 

277.  Head,    Cane,    and   Cordon   Pruning   of 

Vines. 

278.  Olive  Pickling  in  Mediterranean  Coun- 

tries. 

279.  The  Preparation  and  Refining  of  Olive 

Oil   in    Southern    Europe. 

281.  The  Results  of  a  Survey  to  Determine 

the  Cost  of   Producing  Beef  in   Cali- 
fornia. 

282.  Prevention  of  Insect  Attack  on  Stored 

Grain. 

283.  Fertilizing  Citrus   Trees  in  California. 

284.  The   Almond    in    California. 

285.  Sweet  Potato  Production  in  California. 
2S6.   Milk   Houses   for  California  Dairies. 
287.    Potato    Production    in   California. 
1288.    Phylloxera   Resistant  Vineyards. 

289.  Oak  Fungus  in   Orchard  Trees. 

290.  The  Tangier  Pea. 

291.  Blackhead   and   Other   Causes   of  Loss 

of  Turkeys   in   California. 

292.  Alkali   Soils. 

293.  The    Basis    of    Grape    Standardization. 

294.  Propagation    of   Deciduous    Fruits. 

295.  The    Growing   and    Handling   of    Head 

Lettuce   in   California. 

296.  Control     of     the      California      Ground 

Squirrel. 

297.  A  Survey  of  Beekeeping  in  California; 

The  Honeybee  as  a  Pollinizer. 

298.  The    Possibilities    and    Limitations    of 

Cooperative   Marketing. 

299.  Poultry   Breeding:   Records. 

300.  Coccidiosis  of  Chickens. 

301.  Buckeye  Poisoning  of  the  Honey  Bee. 

302.  The   Sugar   Beet   in   California. 

303.  A  Promising  Remedy  for  Black  Measles 

of  the  Vine. 


The  publications  listed  above  may  be  had  by  addressing 

College  of  Agriculture, 

University  of  California, 

Berkeley,  California. 


